Senior System Administrator – Security & Cloud

About the role

We are looking for a Senior System Administrator who will lead the remediation of security vulnerabilities across both on‑premises and cloud environments. The role sits within the Infrastructure team and works closely with Cybersecurity specialists to protect critical enterprise systems.

Key responsibilities

• Research, evaluate, and implement remediation solutions for vulnerabilities identified by tools such as CrowdStrike, Qualys, SentinelOne, and similar platforms.
• Partner with Cybersecurity teams to assess risk and execute remediation plans within defined SLAs.
• Deploy security patches, OS updates, registry modifications, and configuration changes.
• Support and administer Windows Server environments on‑premises and in Microsoft Azure.
• Troubleshoot complex issues involving servers, networking, virtualization, cloud services, and storage technologies.
• Administer VMware environments, including virtual servers and VDI platforms.
• Assist with troubleshooting switches, routers, firewalls, ISP connectivity, and other network‑related challenges.
• Participate in vulnerability management initiatives and continuous infrastructure hardening.
• Follow change control and change management processes for production modifications.
• Occasionally work after‑hours for patching, upgrades, and infrastructure improvements.

Required profile

• 5+ years of experience in Systems Administration, Infrastructure Engineering, or a related field.
• Strong background supporting both on‑premises enterprise infrastructure and Microsoft Azure environments.
• Advanced troubleshooting skills for Windows Server, Active Directory, networking, and virtualization platforms.
• Proven ability to research and implement solutions for infrastructure vulnerabilities.
• Experience working independently and collaborating with Cybersecurity and Infrastructure teams.
• Excellent documentation and communication abilities.

Required skills

• Windows Server
• Active Directory
• Microsoft Azure
• Azure Active Directory / Microsoft Entra ID
• VMware administration and troubleshooting
• VDI platforms
• Cisco networking technologies (switches, routers, firewalls)
• CrowdStrike Falcon
• Qualys
• SentinelOne
• Vulnerability management platforms